2003 2WD Tahoe brake fade

Generally, brake pedal fade is caused by either a small leak (which it sounds like you didn't see any), bad brake fluid (which it sounds like you replaced), a failing master cylinder or brake booster, rear brake adjustment (which I don't exactly recall on your dad's truck) or sometimes a clogged hose/line.

I have two of the 4x4 now and have owned 2 others (but none as "new" as your dads :). My personal experience is that, if the fluid has been replaced as you did, the fade is an indicator of the master cylinder failing.

This may not be your problem. I'm assuming you are doing it yourself, and not having a shop do it for you. If so, good master cylinders are not that expensive and are very easy to change (just be sure to the follow the instructions for primeing it).

I have had the booster go out in my corvette, which started with the brake fade.

If you don't want to start replacing parts, you might have a reputiable shop find the problem. You can pay them for their time, and then do the work yourself, or have them do it for you.

Regardless, brake fade is an indication that not everything is "right" with the system. And should be fixed as soon as possible.

I was thinking boost too This truck also has whats looks to be a electrical hook up to the master with a relief valve? Well thanks for the response

Gms are good for kicking the abs in just before the vehicle stops. The speed sensors in the front wheels tend to creep out from rust buildup between sensor and spindle. You will notice an abrupt pedal drop when the computer fires the abs. The rust buildup behind the sensor changes that wheels speed signal telling the computer that that wheel is stopped earlier than the rest. The computer interprets that as a skid and fires the abs. Removing the sensors and cleaning the spindle takes care of the problem. Ive done hundreds of these. Good luck